The present invention relates generally to digitizing input devices and, more particularly, the present invention relates to the development of a multi-styli pointing/input device operable with a digitizing array within a digitizer apparatus.
Digitizer systems are well known to those skilled in the art. Typically, an electromagnetic array, or other type of system, is responsive to a stylus used by a user to enter data directly upon a grid and to control various computer functions by writing, sketching, or pointing the stylus against the digitizer array. Some embodiments locate the digitizer directly on the monitor; other embodiments separate the two devices. Usually, separate digitizers are utilized where a large work surface is needed compared to the size of the display device such as a monitor screen. Integrated digitizer and display devices are utilized where portability and size are important. As such, various types of computer systems utilize stylus-based technologies and may include portable systems, desktop systems, transportable, or terminal-based systems.
The integrated digitizer-display systems are integrated only in the sense that they are coplanar and are fitted together in a common device. They are not integrated in that a signal processor is required to convert the signals generated by the digitizer into display signals compatible with the display. Thus, additional circuitry and complexity are involved in even the simplest of digitizer-display systems that are integrated for direct input on the same display surface where the digitizer is located.
Several types of stylus input digitizing devices exist in the prior art. One type involves direct contact of a stylus tip against a capacitive-resistive array. As the stylus tip, such as a metal tip or even a user's finger, is placed proximate a selected area of a digitizing pad, a capacitive-resistive circuit within the pad detects the placement of the stylus and computes its location according to well-known mathematical formulas of a grid-based array. Typically, the capacitive-resistive array is used over small areas in devices such as a portable digitizer screen or finger-sensitive mouse pad.
A second prior art system utilizes an electromagnetic digitizer that interacts with a magnetic-tipped stylus or electromagnetic field-generating stylus in entering data and performing actions desired by the user. The tip of the stylus interacts with the field on the digitizer to convey information and data from the user. Typically a grid of intersecting lines produces a field that can be either actively or passively modified by the field generated by the stylus. Crossing lines can sense the field of the tip to generate a responsive signal, or can produce a field altered by the stylus during interaction.
Another embodiment is that of a stylus having an RF transmitter to send signals to the digitizing array, which then detects the transmitted signals utilizing receiving circuits in the array. Alternatively, the pad locations may be coated and the RF signal generated by the stylus interact with the array and are received at a receiver within the stylus itself.
Further, an alternative embodiment may incorporate a light source, such as visible or infrared light placed within the tip of the stylus to reflect off the pad. The stylus uses an imaging device, such as a CCD camera, to detect optically the return signal, and hence the location where the stylus interacts with the digitizer. The system then processes and decodes the received signal and location in order to determine the appropriate information.
Each of these systems has had some success; however, each has limitations that make them difficult or undesirable to use. For example, the direct contact technology is subject to scratches and wear during normal operation and has low durability compared to other technologies.
The wire-grid electromagnetic technology is expensive to implement and requires many individual wires for greater resolution. Additionally, the electromagnetic digitizers typically require a planar magnetic material behind the wire-grid sensor to shield the system from stray magnetic effects. In portable uses, this makes the technology for the system implementing such technology heavier than necessary. In the light-based systems, the stylus needs to be corded to the digitizer array and the need for sophisticated electronics for producing the light source as well as the CCD camera must be incorporated and expanded to achieve such a stylus.
Stylus-based input devices have also been implemented to incorporate multiple styli in the same device. For example, glove-type input devices have been developed that are placed on a user's hand in a glove form with two or more fingers having an input device associated therewith. The different styli utilize a different signal to differentiate each other. Thus, where there are 5 input devices, one for each finger and the thumb, five different signals must be generated and managed. Should a user use two gloves, each with five input styli, then 10 different signals must be generated and managed.
Further, the multi-styli input devices have utilized very complex routines to observe the movement of the user's fingers, such as a particular joint and the distance the finger is moved, for providing data input. Additional electronics and transducers are necessary to measure each joint of each finger as well as to monitor the distance traveled by the user's fingers. As such, this device is expensive and complicated to implement.
Accordingly, what is needed is an improved multi-styli input device and digitizing apparatus utilizing the input device that has greater resolution than the prior art systems, is easier to manufacture, is less complex when implemented within a computer system, and is more durable during actual use.